Blanket for lithographic presses.



F. A. TESSMER.

BLANKET FOR LITHOGRAPHIG PRESSES.

APPLICATION FILED MAY 11, 1907.

Patented June 8, 1909 coextensive .wit

()FFHfil-t.

UnrrED E? FRANK A. TESSMER, OF'ST. LoUrs, nrssounr.

Brahma. i on LI'IHOGRAPHIC rnnss'ns.

Specification of Letters Patent.

Patented June 8, 1909.

Application filed Hey 11,1967. Serial No. 373,086.

Louis, in the State of Missouri, have invented new and useful Irnrovements in Blankets for Lithographingresses, of which the following isa specification. V

"This invention relates to a blanket for litho gfaphing presses, and ithas for'one of its o jects to provide a blanket which is economical,flpossesses comparatively longlife, hi hly e of pro ucin clearerimpressions than is ordinarily ossible.

In t e common form. of printers blankets for lithographin presses, therubber .pad is the canvas backing to which it is attached so that theentire surface of the cylinder is covered; This has been objectionablefor the reasons that at the best, the blanket can be used for only twoor three months because the rubber, is subjected to the action of ink,aint, oil, turpentine, benzin, water and acid on'the parts that are notcovered by the sheet to ire-printed, and furthermore, there isconsiderable waste since the entire surface of the rubber is notemployed to form the cushion or printing surface and due to the factthat the blanket or cushion covers the entire surface of the cylin der,it is impossible to obtain a sharp and clear impression. 1

I overcome the objections above noted by em loying a blanket in whichthe cushion or rub er forming the printing surface is no longer than thesheet to be printed, thereby greatly reducing the cost of the blanket,since there is no superfluous amount of rubcient in operation,andcapable her in the blanket, and since the sheet to be printed coversthe superficial area of the ruber pad or cushion, no parts of'the latterare exposed to the injurious effects of oil, water,

acid, tur entine and the like.

A stil further advantage accompanying the use of my improved printingblanket is the production of a much sharper impression than usual forthe reason that the pad or. cushion bears only on the parts to beprinted and not u on the entire surface of the stone, as is usua y thecase with presses now in use.

With these objects in view and others, as will appear as thedescriptionproceeds, the invention comprises the various novel features ofconstruction and arrangement of parts which will be more fully describedheretion is about three times t inafter and set forth with particularityin the claim appended hereto.

. 1 In the accompanying drawing, which illustrates one of theembodiments of the invention, Figure 1 is a transverse section of acylinder showing the improved blanket applied thereto.

scale. Fig. 3 is a fragmentary sectional view of a modified form' ofblanket showing a double ply cushion or pad.

Similar reference characters are employed to designate correspondingparts throughout the several views.

, Referring to the drawing, 1 designates a c linder of the type usuallyemployed ina 0e lithograph press which is provided with alongitudinally-extending gri per having teeth ,or pins 2 to which the banket is attached at one edge and a stretching rod 3 having teeth orpins 4 and extending longitudinally of the cylinder at a point aproximately diametrically opposite from t e clipper; said stretcherbeing provided in the usual manner with a ratchet and awl mechanism (notshown), whereby the lanket can be tightly stretched. In the presentinstance, the blanket comprises a canvas back- .ing 5 that has itslongitudinal edges attached respectively to the gripper and stretcher.On the canvas is a'rubber ad or cushion 6 which is just the size of thes eets to be printed and this rubber pad is secured to the canvas byfirst ap lying a coat of rubber cement 7 to the blanl et over an areaequal to the cushion and placing a sheet of linen auze 8 Fig. 2 is atransverse section oi" the blanket removed, drawn on an enlarged towhicha'cbat of rubber cement or t e like,

is applied, for receiving the sheet of'rubber 6.

Besi es serving as a binder, the linen gauze holds the pad aconsiderable distance above the surface of the canvas and the totalthickness of the blanket at the ad or cushion orhe thickness 0 thecanvas backing. A blanket constructed in this manner is of-the singleply type and under some conditions, it maybe preferable to increase thenumber of the plies. In a multiple ply blanket, a sheet of hnen gauze 9is cemented to the first sheet of rubber and a second sheet of rubber 10is cemented to. the

gauze 9, as clearly shown, in Fig. 3. After tion is carried on in theusual manner and iii since the pad or cushion of the blanket is onlyproduced.

In. order to illustrate the economy of a blanket oi the presentconstruction, assume that it is desired to employ the blanket one.

medium sized lithographing press having a cylinder taking an ordinaryblanket of thirty-six by forty-two inches, it is well known that theia'rgest sized sheet that can be printed is twenty-eight by forty-twoinches, which leaves a total waste of rubber in the blanket of forty-twoinches long and eight inches wide, or three hundred and thirty-sixsquare inches. Besides being unnecessarily expensive, the blanket hashlarge area exposed to the deleterious effects of oil, acid, water andthe like, and the entire surface of the blanket comes in contact withthe stone. With the present form of blanket, however, the cushion willbeonly twentyeight by forty-two. inches, which is the size of the sheetsprinted, thus reducing the cost about one fourth and increasing the lifeof the blanket/from two to three months, as usual in the ordinaryblanket, to live or months. VVith still smaller sheets to be printed,the economy would be even greater, as will be readily understood bythose famih' iar with the lithographic printing".

From the foregoing description, taken in connection with theaccompanying drawing, 1

; together with the apparatus which I now consider to be the bestembodiment tl'iereof, l. desire to have it understood that the apparatusshown is merely illustrative and that 3 such changes may he made whendesired, as

are within the scope of the claim.

Having thus described the invention, what I. claim 15:-

The herein described blanket for llil1 graphic printing pressesconsisling of :l ':m-

vas backing, a piece of fabric secured to the backing by cement, and arubber impression pad secured to the piece of fabric by ccment, saidfabric and pad being of snbstantially the size of the sheet to be printd r and the canvas backing being of greater length than the fabric andpad, whereby the bucking is adapted to be secured'io the blanketattaching devices of the press.

In testimony whereof, I. alilx my signature in presence of twowitnesses.

FRANK Witnesses:

JAs. H. SonnNK, Enwi). Monnin'rr.

